Hyperkalemia and Wolff-Parkinson-White type preexcitation syndrome

We have presented a well-documented case of hyperkalemia in a patient known to have Wolff-Parkinson-White type preexcitation syndrome. Increased serum potassium level appears to depress or block conduction via the accessory pathway to a greater extent than in the A-V node, i.e. the accessory pathway is more sensitive to hyperkalemia than normal A-V conduction tissue resulting in complete block of conduction in the accessory pathway.